Modular SOEC/SOFC Cell Stacking to Prevent Thermal Bracing

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Solution Overview

Problem

Existing solid oxide fuel cell (SOFC) and high-temperature electrolysis (HTE) systems face mechanical blocking issues due to the limited number of electrochemical cells in stacks, leading to bracing problems during thermal conditioning, which affects the normal functioning of the devices.

Innovation Solution

The solution involves preassembling modules with a stack of solid oxide electrochemical cells, using conductive ceramic materials or gold grids for electrical contact, and seals like pierced mica sheets or glass beads to ensure leaktightness and improved crushability, allowing for a larger number of cells without mechanical blocking, and a process for producing these modules with thermomechanical treatment to finalize contact members and seals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the number of electrochemical cells in a stack is increased to improve productivity, then hydrogen and oxygen production increases, but mechanical blocking and bracing problems occur during thermal conditioning

Engineering Contradiction:

Improvehydrogen and oxygen productionVSAvoidmechanical stability during thermal conditioning

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent divides the stack into multiple modular units, each containing a manageable number of electrochemical cells (e.g., 10-20 cells per module). These modules are then assembled in series to achieve the desired total cell count and production capacity. This segmentation prevents mechanical blocking issues while maintaining high productivity, as each module can be independently conditioned and assembled without requiring the entire large stack to be handled as one unit.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If conventional nickel grids are used for electrical contact to reduce cost, then manufacturing cost decreases, but electrical contact quality and device performance are insufficient

Engineering Contradiction:

Improvemanufacturing costVSAvoidelectrical contact quality

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent employs composite electrical contact structures that combine conductive ceramic materials (such as doped barium titanate or lead zirconate titanate) with metallic grids. The ceramic layer provides high-temperature stability and improved electrical contact quality, while the metallic component maintains cost-effectiveness and mechanical strength. This composite approach resolves the contradiction between cost and performance by integrating materials with complementary properties.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If seals are made more crushable to improve assembly, then ease of assembly increases, but leaktightness around gas inlet/outlet may be compromised

Engineering Contradiction:

Improveease of assemblyVSAvoidleaktightness

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent implements seals with spatially varying properties: the main body of the seal is designed to be softer and more crushable to facilitate assembly and accommodate misalignments, while the sealing edges contacting the gas inlet/outlet ports are reinforced with harder, more resilient material to ensure reliable leaktightness. This local differentiation of material properties allows the seal to simultaneously provide ease of assembly and maintain sealing integrity under operating conditions.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables the production of electrochemical devices with a larger number of cells without bracing problems, ensuring proper thermal conditioning and functioning, while allowing for easy replacement of defective modules and modulating voltage and power levels.

Implementation Method 1

at least one electrical contact member is arranged between two adjacent modules with contact between their stiffening plates

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

at least one seal is arranged between two adjacent modules to ensure the leaktightness around each gas inlet/outlet from one module to another

Methodology Applied

Scientific EffectSealing:

Implementation Method 3

high-temperature water electrolysis (HTE, high-temperature electrolysis, or HTSE, high-temperature steam electrolysis)

Methodology Applied

Scientific EffectElectrolysis: Electrolysis

Implementation Method 4

a process for producing these modules with thermomechanical treatment to finalize contact members and seals

Methodology Applied

Scientific EffectThermomechanical treatment: Thermomechanical Effect

Data Source

PatentUS11888183B2Electrolysis or co-electrolysis reactor (SOEC) or fuel cell (SOFC) with electrochemical cell stacking by preassembled modules, and associated production process

Publication Date: 2024.01.30 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

AI summary

An electrochemical device may be formed by assembly by stacking preassembled modules, each of these modules being produced as a usual stack of electrochemical cells. The manufacture of preassembled modules can make it possible to produce electrochemical devices with a large number of electrochemical cells, without the bracing problems present and excessive crushing courses that are encountered in the cell stacks according to the prior art, i.e., in a single block.